If Grant hasn’t repeated his phenomenal play from the second half of the 2007 season, when he rushed for 929 yards and a 5.1-yard average per carry in the final 10 games, he also showed last season he wasn’t the more pedestrian runner from 2008 who gained only 3.9 yards a rush playing through a hamstring injury.

So, what is he after three seasons and 776 carries as their primary back? A tough, physical runner who can handle a heavy workload, a back who shows some power and burst but with only OK ability to avoid tacklers.

That came through last year when, as a healthy 16-game starter, Grant got enough out of his 282 runs to finish with more yards (1,253) than one of the six NFL backs who had more carries (Cincinnati’s Cedric Benson), though not enough to prevent one player who had fewer carries (Baltimore’s Ray Rice, 254 carries for 1,339 yards) from surpassing Grant in yardage.

That puts Grant on a three-year run in which his 3,362 yards rushing trails only Minnesota’s Adrian Peterson (4,484), Kansas City’s Thomas Jones (3,833) and St. Louis’ Stephen Jackson (3,460) over that time. Total yards is only one measure of a runner’s effectiveness and, for instance, doesn’t take into account better backs who play for teams that have superior depth at halfback. But the 27-year-old Grant probably will get the large majority of the Packers’ carries for a fourth straight season in a well-rounded offense that figures to be one of the best in the NFL.

“Those (last) three years, there’s really been only one other back that you can say was more productive, and that was Adrian Peterson,” said Edgar Bennett, the Packers’ running backs coach. “A lot of things with Grant (not repeating ’07), he had the injuries. (But) he has to improve in some areas as well, when we get out there in a one-on-one battle (against a tackler), we’ve got to win that battle. When we get on that second (i.e., linebacker) level, we expect him to win those battles.”

The difference from Grant in 2007 and the last two seasons has been the game-changing big run.

In only 10 games in ’07 after he became the primary back, Grant had 11 runs of 20 yards or more, including four touchdowns that ranged from 27 yards to 66 yards. In 16 games as the primary back in ’08, after he injured his hamstring in training camp, that number plummeted to only four runs of 20 yards or more. Last year, back at full health for 16 games, he crept up to seven runs of 20 yards or more, including touchdowns of 56 yards and 62 yards in the final month of the season.

Behind Grant, General Manager Ted Thompson drafted a running back this year for the first time since 2007, the University of Buffalo’s James Starks in the sixth round. Though that’s hardly a premium pick, the Packers selected Starks for a reason and think he might have the athletic ability to force his way onto the field occasionally as a rookie.

They’re also looking at him as a possible successor to Grant as a primary back. Grant has two years left on a contract that will play him $4.5 million in salary and bonuses this season and $5.5 million in 2011, after which he’ll be 29, an age at which the large majority of NFL backs begin to decline.

Starks is built similarly to Grant — both are relatively tall for the position, Grant at 6-foot-1 and Starks at 6-2, and weigh in the 220-pound range. At least in nonpadded practices, Starks also looks the more agile and athletic of the two, but toughness and power are crucial to success for an NFL back, and the Packers won’t get a sense until the preseason games whether Starks comes close to measuring up to Grant in those areas.

“(Starks) is explosive, that’s what jumps out more than anything else,” Bennett said. “Has tremendous read, very good change of direction. And he has good hands coming out of the backfield. Just like any young guy coming into our system, it takes time.”

Unless Starks picks up pass protection quickly, fourth-year pro Brandon Jackson figures to be the third-down back for another year. Jackson’s a far superior receiver to Grant and has become an excellent pass protector the past couple of years.

Also back with a shot at making the roster is Kregg Lumpkin, who spent most of 2008 on injured reserve and all of last year on the practice squad.

It seems unlikely the Packers would keep three fullbacks for a second straight season, so as long as 2009 fifth-round pick Quinn Johnson shows well enough, either Korey Hall or John Kuhn could be cut after three seasons with the team. The Packers are looking for Johnson (6-1 and 263) to become a bulldozer blocker this year.

“He’s more of a true thumper,” Bennett said. “You put those pads on you’ve got a big, strong guy in there.”